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separation density prediction of geldart A^(-)dense medium in gas-solid fluidized bed coal beneficiators

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Particuology 2024年第9期92卷 251-262页

作者： Chenyang Zhou Chengguo Liu Yue Yuan Zhijie fu Jesse Zhu Chenlong Duan school of Chemical Engineering and Technology China University of Mining and TechnologyXuzhou221116China Particle Technology Research Centre Western UniversityLondonOntarioN6A 5B9Canada

Gas-solid Fluidized Bed Coal Beneficiator(GFBCB)process is a crucial dry coal beneficiation fluidization *** work employs the GFBCB process alongside a novel Geldart A^(-)dense medium,consisting of Geldart A magnetite particles and Geldart C ultrafine coal,to separate small-size separated objects in the *** effects of various operational conditions,including the volume fraction of ultrafine coal,the gas velocity,the separated objects size,and the separation time,were investigated on the GFBCB's separation *** results indicated that the probable error for 6∼3 mm separated objects could be controlled within 0.10 g/cm^(3).Compared to the traditional Geldart B/D dense medium,the Geldart A/A^(-)dense medium exhibited better size-dependent separation performance with an overall probable error 0.04∼0.12 g/cm^(3).Moreover,it achieved a similar separation accuracy to the Geldart B/D dense medium fluidized bed with different external energy for the small-size object *** work furthermore validated a separation density prediction model based on theoretical derivation,available for both Geldart B/D dense medium and Geldart A/A^(-)dense medium at different operational conditions.

关键词： GFBCB Geldart A^(-)dense medium separation density separated objects size Prediction model

Critical precipitation behavior of MnTe inclusions in resulfurized steels during solidification

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International Journal of Minerals,Metallurgy and Materials 2024年第8期31卷 1849-1857页

作者： Xiangyu Xu Lu Zhang Zifei Wang Qianren Tian Jianxun fu Xuemin Wang Center for Advanced solidification Technology(CAsT) School of Materials Science and EngineeringShanghai UniversityShanghai 200444China state Key Laboratory of Advanced special steel Shanghai UniversityShanghai 200444China Collaborative Innovation Center of steel Technology University of Science and Technology BeijingBeijing 100083China Yangjiang Branch Guangdong Laboratory for Materials Science and Technology(Yangjiang)Advanced Alloys LaboratoryYangjiang 529500China

Te treatment is an effective method for modifying sulfide inclusions,and MnTe precipitation has an important effect on thermal brittleness and steel corrosion *** most actual industrial applications of Te treatment,MnTe precipitation is *** critical precipitation behavior of MnTe inclusions was investigated through scanning electron microscopy,transmission electron microscopy,machine learning,and first-principles *** preferentially precipitated at the container mouth for sphere-like sulfides and at the interface between Mns grain boundaries and steel matrix for rod-like *** Mns/MnTe interface was semicoherent.A composition transition zone with a rock-salt structure exhibiting periodic changes existed to maintain the semicoherent *** critical precipitation behavior of MnTe inclusions in resulfurized steels involved three stages at varying ***,Mn(s,Te)precipitated during ***,MnTe with a rock-salt structure precipitated from Mn(s,Te).Third,MnTe with a hexagonal NiAs structure transformed from the rock-salt *** solubility of Te in Mns decreased with decreas.ng *** critical precipitation behavior of MnTe inclusions in resulfurized steels was related to the Mns precipitation *** the increase in Mns precipitation temperature,the critical Te/s weight ratio *** consideration of the cost-effectiveness of Te addition for industrial production,the Te content in resulfurized steels should be controlled in accordance with Mns precipitation temperature and s content.

关键词： resulfurized steels modification of inclusion manganese telluride precipitation

Reactive molecular dynamics insight into the thermal decomposition mechanism of 2,6-Bis(picrylamino)-3,5-dinitropyridine

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Defence Technology（防务技术） 2024年第3期33卷 134-146页

作者： Jianbo fu Hui Ren Xinzhou Wu Yongjin Chen Mi Zhang Yazhi Cheng state Key Laboratory of Explosion science and Technology Beijing Institute of TechnologyBeijing 100081China

2,6-bis(picrylamino)-3,5-dinitropyridine(PYX)has excellent thermostability,which makes its thermal decomposition mechanism receive much *** this paper,the mechanism of PYX thermal decomposition was investigated thoroughly by the ReaxFF-lg force field combined with DFT-B3LYP(6-311++G)*** detailed decomposition mechanism,small-molecule product evolution,and cluster evolution of PYX were mainly *** the initial stage of decomposition,the intramolecular hydrogen transfer reaction and the formation of dimerized clusters are earlier than the denitration *** the progress of the reaction,one side of the bitter amino group is removed from the pyridine ring,and then the pyridine ring is *** final products produced in the thermal decomposition process are CO_(2),H_(2)O,N_(2),and H_(2).Among them,H_(2)O has the earliest generation time,and the reaction rate constant(k_(3))is the *** clusters are formed during the decomposition of PYX,and the formation,aggregation,and decomposition of these clusters are strongly affected by *** low temperatures(2500 K-2750 K),many clusters are *** high temperatures(2750 K-3250 K),the clusters aggregate to form larger *** 3500 K,the large clusters decompose and become *** the late stage of the reaction,H and N in the clusters escaped almost entirely,but more O was trapped in the clusters,which affected the auto-oxidation process of ***'s initial decomposition activation energy(E_(a))was calculated to be 126.58 kJ/*** work contributes to a theoretical understanding of PYX's entire thermal decomposition process.

关键词： PYX Thermal decomposition ReaxFF-lg MD simulations Excellent thermostable explosives

Effects of Atmospheric Pressure on Developmental Characteristics and the stability of Air Entraining Agent for Concrete

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Journal of Wuhan University of Technology(Materials science) 2024年第4期39卷 979-989页

作者：李立辉牛开民 TIAN Bo CHEN Xin fu Ziqian ZHU Xuwei school of Civil Engineering Chongqing Jiaotong UniversityChongqing 400074China Transportation science and Engineering Harbin Institute of TechnologyHarbin 150090China Research Institute of Highway Ministry of TransportBeijing 100088China

In order to ascertain the effects of atmospheric pressure on developmental characteristics and the stability of AEA(air-entraining agent)solution bubbles,AEA solution experiments and AEA solution bubble experiments were,respectively,conducted in Peking(50 m,101.2 kPa)and Lhasa(3,650 m,63.1 kPa).surface tensions and inflection-point concentrations were tested based on AEA solutions,whilst developmental characteristics,thicknesses and elastic coefficients of liquid films were tested based on air bubbles of AEA *** study involved three types of AEAs,which were TM-O,226A,and *** experimental results show that initial sizes of TM-O,226A,and 226s are,respectively,increased by 43.5%,17.5%,and 3.8%.With the decrease of ambient pressure,the drainage rate and the drainage index of AEA solution bubbles *** experiments show that the liquid film thicknesses of all tested AEA solution bubbles are in micron *** the atmospheric pressure decreases from 101.2 to 63.1 kPa,the liquid film thicknesses of three types of AEA solutions decrease in various degrees;and film elasticities at critical thicknesses *** film of 226s solution bubbles is the most stable,presenting as a minimum thickness *** should be noted that elastic coefficient of liquid film only represents the level at critical thickness,thus it can not be applied as the only evaluating indicator of bubble *** a type of AEA,factors affecting the stability of its bubbles under low atmospheric pressure include initial bubbles size,liquid film thickness,liquid film elasticity,ambient temperature,etc.

关键词： air-entraining agent surface tension bubble size liquid film thickness liquid film elasticity atmospheric pressure

soil bacterial and fungal communities resilience to long-term nitrogen addition in subtropical forests in China

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Journal of Forestry Research 2024年第2期35卷 95-108页

作者： Xinlei fu Yunze Dai Jun Cui Pengfei Deng Wei Fan Xiaoniu Xu school of Forestry and Landscape Architecture Anhui Agricultural UniversityHefei 230036AnhuiPeople’s Republic of China suzhou Polytechnic Institute of Agriculture Suzhou 215008JiangsuPeople’s Republic of China College of Life and Environment sciences Huangshan UniversityHuangshan 245041AnhuiPeople’s Republic of China

Atmospheric nitrogen(N)deposition is predicted to increase,especially in the ***,the responses of soil microorganisms to long-term N addition at the molecular level in N-rich subtropical forests have not been clarified.A long-term nutrient addition experiment was conducted in a subtropical evergreen old-growth forest in *** four treatments were:control,low N(50 kg N ha^(-1)a^(-1)),high N(100 kg N ha^(-1)a^(-1)),and combined N and phosphorus(P)(100 kg N ha^(-1)a^(-1)+50 kg P ha^(-1)a^(-1)).Metagenomic sequencing characterized diversity and composition of soil microbial communities and used to construct bacterial/fungal co-occurrence ***-treated soils were more acidic and had higher levels of dissolved organic carbon than *** were no significant differences in microbial diversity and community composition across *** addition of nutrients increased the abundance of copiotrophic bacteria and potentially beneficial microorganisms(e.g.,Gemmatimonadetes,Chaetomium,and Aureobasidium).Low N addition increased microbiome network *** rare fungi were identified as module hubs under nutrient addition,indicating that low abundance fungi were more sensitive to increased *** results indicate that the overall composition of microbial communities was stable but not static to long-term N *** findings provide new insights that can aid predictions of the response of soil microbial communities to long-term N addition.

关键词： Long-term nitrogen addition Old-growth subtropical forest Metagenomics Beneficial microorganisms Co-occurrence network

Novel Hf_(x)Ta_(1−x)C solid solution nanowire toughened HfC coating:An effective strategy for synchronous enhanced mechanical and anti-ablation performance

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Journal of Advanced Ceramics 2024年第5期13卷 590-601页

作者： Hui Chen Yulei Zhang Yanqin fu Wenhan Gai Junhao Zhao Haohui Zhang shaanxi Key Laboratory of Fiber Reinforced Light Composite Materials Northwestern Polytechnical UniversityXi’an 710072China Henan Key Laboratory of High Performance Carbon Fiber Reinforced Composites Institute of Carbon Matrix CompositesHenan Academy of SciencesZhengzhou 450046China

Ultra-high-temperature ceramic nanowires have shown increas.ng potential for use as thermal structural ***,novel s.ngle-crystal Hf_(0.5)Ta_(0.5)C solid solution nanowires were synthesized and incorporated with a HfC coating to construct a robust structure with Hf_(0.5)Ta_(0.5)C solid solution nanowires uniformly distributed and interconnected within the *** novel Hf_(0.5)Ta_(0.5)C solid solution nanowires could effectively hinder crack propagation through crack tip pinning and crack *** mechanism substantially enhanced the elastic modulus and fracture toughness of the HfC coating by 53.29%and 59.67%,*** toughened HfC coating displayed superior fracture toughness and good interfacial binding strength with the substrate to resist severe oxidation and ***,the high thermal conductivity of the toughened HfC coating promoted heat ***,in comparison to the pure HfC coating,the toughened HfC coating displayed smaller mass and linear ablation rates of−0.35 mg·s^(−1)and−0.46μm·s^(−1),which decreased by 39.66%and 36.98%,*** work not only simultaneously enhances the mechanical properties and ablation resistance of HfC-coated carbon/carbon(C/C)composites but also provides novel prospects for advanced ultrahigh-temperature ceramic nanowires under extreme conditions.

关键词： Hf_(x)Ta_(1−x)C solid solution nanowires HfC coating carbon/carbon(C/C)composites mechanical performance ablationresistance

A grapefruit microstructure fiber temperature sensor coated with liquid crystal based on waist-enlarged taper

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Optoelectronics Letters 2024年第3期20卷 142-146页

作者： WAng Feng LI Jiaxuan ZHAng Rongjing fu Xinghu College of Mechanical and Electrical Engineering Hebei Normal University of Science&TechnologyQinhuangdao 066004China school of Information science and Engineering Key Laboratory for Special Fiber and Fiber Sensor of Hebei ProvinceYanshan UniversityQinhuangdao 066004China

In this paper, a grapefruit microstructure fiber(GMF) temperature sensor coated with liquid crystal(LC) based on waist-enlarged taper is proposed and fabricated, and its temperature sens.ng characteristics are analyzed. The waist-enlarged taper is formed at the fusion point between s.ngle mode fiber(sMF) and GMF. The capillary glass tube is sleeved outside GMF, LC is filled into the capillary glass tube, and its two ends are finally sealed to form a sensor. The experimental results show that when the length of GMF is 2.5 cm, the temperature sensitivity of the sensor can reach up to 195.3 pm/℃ in the range of 30-90℃, and it has a good stability for reuse. Thereby, it can be used in biochemical, industrial production and other temperature detection areas.

关键词： capillary fiber microstructure

Porous s-doped carbon nitride foam with accelerated charge dynamics for synchronous photocatalytic hydrogen production and highly selective oxidation of amines

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Nano Research 2024年第8期17卷 6860-6869页

作者： Yu He Aiping Wu Nan Wang Ying Xie Chungui Tian Honggang fu Key Laboratory of functional Inorganic Material Chemistry(Ministry of Education of the People’s Republic of China) Heilongjiang UniversityHarbin 150080China

Photocatalytic hydrogen evolution coupled with organic oxidation holds great promise for converting solar energy into high-valueadded chemicals,but it is hampered by sluggish charge dynamics and limited redox ***,a porous s-doped carbon nitride(s-C_(3)N_(4−y))foam assembled from ultrathin nanosheets with rich nitrogen vacancies was synthesized us.ng a molecular selfassembly *** s dopants and N vacancies synergistically adjusted the band structure,facilitating light absorption and enhancing the oxidation ***,the ultrathin nanosheets and porous structure provided more exposed active sites and facilitated mass and charge ***,s-C_(3)N_(4−y) foam exhibited enhanced photocatalytic activities for synchronous hydrogen evolution(4960μmol/(h·g))and benzylamine oxidation to N-benzylidenebenzylamine(4885μmol/(h·g))with high selectivity of>99%,which were approximately 17.6 and 72.9 times higher than those of bulk CN,*** photocatalytic coupling pairing reaction promotes the water splitting by consuming H2O2,thereby improving the hydrogen evolution efficiency and achieving the production of high value-added *** study provides an effective route for regulating the morphology and band structure of carbon nitride for synthesizing highly valuable chemicals.

关键词： photocatalysis s-doped carbon nitride band structure regulation hydrogen evolution coupled with benzylamine oxidation reaction mechanism

Nd^(3)+:YAG-Al_(2)O_(3) nanocrystalline transparent ceramics with high inflexion concentration quenching of Nd^(3+) prepared by amorphous crystallization

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Journal of Advanced Ceramics 2024年第8期13卷 1242-1253页

作者： Xiujuan Wan Guangfan Tan Liang Cai Jie fu Jianqiang Li Yingchun Zhang school of Materials science and Engineering University of Science and Technology BeijingBeijing 100083China state Key Laboratory of New Ceramics and Fine Process.ng School of Materials Science and EngineeringTsinghua UniversityBeijing 100080China state Key Lab for Mesoscience and Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China

Rare earth ion-doped Y_(3)Al_(5)O_(12)(YAG)-based transparent ceramics have been used as important laser gain media for a long time,yet the doping concentration of active ions is limited due to concentration quenching,wherein the inflexion concentration quenching of Nd^(3+)is recognized as 1.0 at%.In this work,YAG-Al_(2)O_(3) nanocrystalline transparent ceramics with a concentration of Nd^(3+)(O-5.0 at%)were fabricated via amorphous crystallization,and the crystal structure evolution,morphology,and optical properties were systematically investigated by differential scanning calorimetry(DsC),X-ray powder diffraction(XRD),transmission electron microscopy(TEM),magnetic resonation(MAs),nuclear magnetic resonation(NMR),and fluorescence *** doping of Nd^(3+)can promote the transition of Al[5]and Al[6]to Al[14],indicating improvements in the ability of the amorphous material to form Nd^(3+):Y_(2)O_(3)-Al_(2)O_(3) vitrified beads,and 1.5 at%Nd^(3+):YAG-Al_(2)O_(3) nanocrystalline transparent ceramics can be obtained by crystallization at 1050℃ with a matrix composed of YAG and concomitant δ-Al_(2)O_(3) and θ-Al_(2)O_(3).The nanocrystalline transparent ceramics show an internal transmitance of 89.56%at 1064 nm,and the strongest emission peak corresponds to the energy transfer from 4F_(3/2) to 4l_(11/2) of Nd^(3+)with a fluorescence lifetime of 231μs when pumped by an 808 nm ***,spectral broadening begins to occur,indicating the onset of concentration quenching,when the concentration of Nd^(3+)exceeds 1.5 at%,substantially higher than the 1.0 at% observed in YAG ***-Al_(2)O_(3) nanocrystalline transparent ceramics obtained by amorphous crystalization can be utilized as the matrix to increase the inflexion point of doping concentration quenching of Nd^(3+),and this material may have great potential as a laser gain medium.

关键词： Y_(3)Al_(5)O_(12)(YAG)-Al_(2)O_(3) nanocrystalline transparent ceramics laser gain medium Nd^(3+)